So when I was a wee tot, I was terrified of my dad’s monster face. Not the same as the angry face he made when I was in trouble, but the face he made when doing adult stuff: Reading the paper; writing on his notepad (doing math. He did math at home); untying a fishline knot, whatever.
Decades later, I would learn I have my own similar monster face which I discovered in a mirror selfie, figuring out how to operate my phone camera. (It was 2007, they were still new-ish and unstandardized). It turns out scary faces for concentrating on tasks are hereditary.